Sebastian Schumann

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Got a lot of stuff going on right now, hope after defending my last project before the dissertation work this Friday things get more relaxed and I can write a bit more again.

For those who wonder, the code in the beginning is to verify my blog on Empire Avenue.

And YES, this includes some OpenSIPS configuration files for Mediaproxy integration, as still many ppl. land here after searching for it.

First of, I know I have the OpenSIPS config files outstanding since like ever, but I cannot promise more than it will be published “soon”.

In the mean time, let me share my experience with my newly received mobile internet USB dongle

I use a Huawei E1750 HSPA USB dongle to connect with T-Mobile here in Slovakia and I have to say it works surprisingly great. That might not be a big surprise, but considering I use the device on Win (rarely), Mac OS X and mainly Linux, I wanted to share that I am really happy how the device performs with all three operating systems.

While Huawei offers software for Windows (straight forward, this might help for Windows 7 though: http://bit.ly/hWRNgb) and Mac OS X (pretty straight forward, not too much to write about), I wanted to quickly share my linux experience.

When I plugged the device first time, it has not been recognized (lsusb just showed another Linux Foundation Root Hub device). I installed the usb-modeswitch packages and when I plugged the device, it was recognized.

ID 12d1:140c Huawei Technologies Co., Ltd.

The easiest to connect then seemed the sakis3g wrapper (http://www.sakis3g.org/). I downloaded the binary-free version and ran it. Surprisingly, the GUI immediately showed up in GNOME.

After selecting “Connect to 3G” I had to enter the admin password. After confirmation, I could select the interface (I used “Interface #0″, but I tried connecting my Nokia E72 where I had to select #1. I guess trial-and-error should help if #0 is not working for you.).

After entering the PIN I only had to select the AP (“internet” has been entered already) and I was online

The tool let’s you then disconnect or get some connection information.

If you need to monitor your data use (Win and Mac tools can collect monthly usage but sakis3g only shows the one for the current connection), I would recommend to simply use vnstat and let it monitor the ‘ppp0′ interface. Note that if you connect to a VPN or dial-up the same interface might be used. As that was not the case for me, I have now 3G working with Linux as well and can also monitor my monthly consumption there.

I’ll try to start writing more often (hmm, better say, start at all again) in my blog. Even have some half written posts ready, to be published in the upcoming weeks

I want to start off by noticing that I launched just yesterday the newly designed web site of the shooting club I am a member of.

Whoever is interested can visit www.sg-schreiersgruen.de (website is German). Comments are welcome

I did a lecture at the university today about details of IMS Signaling.

Some content is like my old presentation some posts ago, I just added a few important points for understanding. The presentation is meant as supplement of the lecture and is not so usable stand-alone.

Besides the slides, the following has been discussed:

• SIP routing (Via, Record-Route)
• SIP terminology (message, transaction, dialog; out-of-dialog, in-dialog)
• Path/Service-Route compared to Record-Routing procedure
• Implicit Set registration if we have two implicit sets on two IMPIs sharing the same IMPU
• SUBSCRIBE/NOTIFY as part of SIP extension with notification framework in order to inform client about server side events. Comparison to SIP.
• REGISTER authentication difference to SIP (INVITE w/o registration or not)
• Discovery of next nodes (CSCF) during registration (DNS, HSS query) and for sessions (Service-Route/Path discovery for originating/terminating requests)
• Test suggestion on OpenIMS platform (mix user identities, multiple S-CSCF, interconnect IMS networks)

I added a new page where I listed all projects that I did together with students.

In case you are interested in this work or see some potential cooperation possibilities – or are a good student and interested in continuing the work – please feel free to contact me.